Attachment for carpenters&#39; squares.



PATENTED JULY 3, 1906.

R. L. MGGARTNEY. ATTACHMENT FOR GARPENTERS SQUARES.

APPLICATION FILED JAN. 18, 1905.

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UNTTED sTATEs PATENT oEEioE.

ATTACHMENT FOR CARPENTERS SQUARES.

Specification of Letters Patent.

Patented J' uly 3, 1906.

Application filed January 18,1905. Serial No. 241,685.

T0 all whom, it may concern:

Be it known that I, ROBERT L. MoCAR'r- NEY, a citizen of the United States, residin at Ottumwa, in the county of Wapello and State of Iowa, have invented new and useful Improvements in Attachments for Carpenters Squares, of which the followingis a specification.

This invention relates to an attachment for carpenters squares for the purpose of enabling an operator to accurately ascertain desired cuts in lumber and rafters and also the length of the latter, as Well as facilitating the erection of stair-horses and other like structures.

The attachment is applied to an ordinary carpenters square; and it consists, essentially, Vof a double bar or length-dening member, preferably graduated to twelfths and representing one inch to a foot, said bar or length member cooperating with one arm of the square and adjustably attached to a set slide on the remaining arm of the square, and an arcuate slide or rise member adjustably attached to the bar or length member and the slide.

The invention also consists of details of construction and arrangement of the several parts, whichwill be more fully hereinafter set forth.

In the drawings, Figure 1 is a plan view of a carpenters square, showing the attachment applied thereto. Fig. 2 is an irregular section taken on the line 2 2, Fig. 1. Fig. 3 is a transverse vertical section on the line 3 3, Fig. 1.

Similar numerals indicate corresponding parts in the different views.

The numeral 1 designates a carpenters square of ordinary form, having arms 2 and 3, the arm 3 being longer than the arm 2 and both arms graduated to represent inches and fractions of the latter. On the arm 3 a slide 4 is disposed and provided with a setscrew 5 for maintaining a fixed adjustment thereof, the said slide having at one end a projection 6 and at the opposite end a fulcrum extension 7. The extension 7 is projected alonfxr the outer edge of the arm 3 and formed wit an arcuate slot 8, to which one end of a double bar or length member 9 is adjustably held by a set-screw 10. This double bar or length member 9 spans or is movable over both arms 2 and 3 of the square, and at opposite points therein with relation to the arm 2 set-screws 11 and 12 are located to clamp the bar or member in tight engagement with the said arm 2. The free end of the bar or member 9 projects far enough beyond the outer edge of the arm 2 of the square to be of practical service in laying out different kinds of work, and the said end is terminally closed by a space-block or analogous device 13, securely riveted or otherwise fastened thereto. The bar or length member 9 is graduated to twelfths, representing one inch to a foot, and the scale thereon cooperates with the graduations of the arm 2. Secured at one end of the bar or length member 9 is an arcuate arm 14, having a slot 15 extending longitudinally thereof and engaged by a set-'screw 16, entering the projection 6 of the slide 4, the means for securing the said arm to the bar or length member being preferably in the form of a set-screw 17, so that an adjustment can be readily made or a separation ensue when it is desired to disconnect the attachment from the square. The arm 14 will also be provided With suitable graduations 18, representing in proper proportion with respect to the other scales of adjustment of the remaining members of the attachment the rise per foot, and hence the arm 14 may be properly termed a rise-indicating member.

The arcuate slot 8 insures a regular movement of the length member 9 in an arcuate plane over the arm 2 when the pivot device 10 is shifted in the said slot to regularly bring the graduations on the said length member over the graduations of the arm 2. The range of adjustment of the member 9 is also materially increased by the provision of the arcuate slot 8, in that the -pivot or clamping element 1() may be shifted longitudinally ofthe said slot 8. The slot 8 also renders the movement of the member 9 constant and devoid of any irregularity. The arm 14 is constructed of elongated arcuate form to also increase the range of adjustment of the member 9, and the elongated slot 18 therein preserves the uniformity of movement of the member 9 when the ivot or clamping element 10 is adjusted in t e slot 8, without in the least detracting from the accuracy of measurement derived from the use of the arm 14, it being observed that the pivot or clamping element 17 connecting the arm 14 with the member 9 always remains in one position with respect to said member. The arm 14 is also approximately of the same curvature as the surface of the earth, or, in other words, practically con- IOO IIO

the movement of the member 9 and to renderv the graduations more discernible or easily readable, the arm 14 is constructed to move across the extremity 6 of the slide 4 instead of over the body of the slide, and such disposition of the arm is particularly beneficial in view of its elongated structure in permitting the length member to have a large range of adjustment. Another advantage in the slots 8 and 18 is that the member 9 may be maintained at one angular position with respect to the horizontal and the slide 4 permitted to be shifted without modifying such angular position and to indicate different measurements on the arm 3 of the square. This latter advantage is particularly important in this class ofdevices, and such angular retention of the member 9 is permitted, as will be understood, in view of the shiftable pivot 10, which engages the slot 8 and the elongated slot 18, as Well as the elongated arm 14.

Non corrosive metal will be preferably used in the construction of the several parts of the attachment, and the set-screws will have heads of such nature as to render them easily operated in setting or adjusting the several parts of the attachment.

It will be observed that the attachment is applied to an ordinary form of try-square, and, further, that it is not required in the least to mutilate by slots or other means the arms of the square. The proportions of the several parts of the attachment will be such as to render them easily applicable and operative vin connection with a try-square or with several squares having diHerent dimensions. The attachment gives to an ordinary trysquare an extended service and may be applied to squares already in use. Y

To explain one use of the attachment in connection with a try-square, let it be supposed that it is desired to cut rafters for a house eighteen by twenty feet with a nineinch rise per foot. The set-screw 1 6 is loosened and also the set-screw 5, and the slide 4 is then moved until it coincides with 12 on the arm 3. The bar or length member 9 is then elevated until it will indicate nine inches per foot, it being understood that the screws 11 and 12 will rst be loosened before adjusting the said bar or length member 9, and the slide 4 is then shoved up to nine inches on the arm 3, which represents one-half the width of the house, and the bar or length member will register eleven feet three inches, the length of the rafters to be cut, and also gives the bottom and top cuts for the rafters. By

vment of the slide 4. The member 9 registers the length proportionately to the rise per foot and the dimensions of the rafters to be cut with respect to the width and height of the complete structure, and said slide registers the base or half the width of the house in relation to the stated scale or dimensions of the house or structure.

In this connection it will be noted that the arm 14 is not struck f from any part of the attachment as a center, but as an independent arc, and in the adjustment of the slide 4 with respect to this armV and the elevation of the length member 9 on the arm 2 of the square care will be taken to closely observe and preserve the inch rise per foot that may be necessary to obtain the proper inclination or length designated by the member 9. There will be, however, no difliculty in accurately arriving at the result sought by reason of the fact Ithat the elevation of the length member 9 in registration with respect to the square-arm 2 will always be proportionate to the movement of the slide 4 on the arm 3 and the arm 14. After the necessary adjustment has been obtained the screws 11 and 12 will be tightened to maintain the several parts in the position desired for laying out the rafters.

It will be understood that angles or inclinations indicated by the adjustment of the several parts of the attachment may be varied indefinitelywithin the scope or operation of the same and the length of the square-arms.

By the use of the im roved attachment it will be found that wor may be laid out or material cut with expedition and accuracy, and when the use of the attachment is not desired it may be removed and stored in compact form within a tool-chest or other inclosure.

Having thus described the invention, what is claimed is- 1. In combination 'with a square, of a length-indicating member adjustably engaging one of the arms thereof and graduated to twelfths, a slide adjustably held on the remaining arm of the square and having an outer' terminal longitudinal extension with an arcuate slot therein to which one end of the length-indicating member is adjustably"A and loosely pivoted, and an elongated arcuate rise-indicating member adj ustably connected to the inner extremity of the slide and also pivotally attached near one end of the lengthindicating member, the-rise-indicating member being struck from a center other than'the TOO IIO

point of' pivotal attachment of the length! dicating member to the slide.

2. The combination with a square having the usual graduations, of a bar adjustably mounted on one arm thereof and having clamping means for rigidly securing it in adjusted position, the said bar being graduated to designate tWelths, a slide adjustably mounted on the remaining arm of the s nare and having the ends projected beyon the side edges of said arm, the outer end of the slide having a longitudinal extension with an arcuate slot in the free extremity thereof with which one end ofthe bar adjustably cooperates, and a rise-per-foot-indicating member movably attached to the bar and adjustably extending across the inner projecting ends of the slide, said rise-per-foot-indicating member being of elongated arcuate form and having its center of curvature eccentric to the point of attachment of the bar to the outer end extension of the slide.

In testimony whereof I have hereunto set my hand in presence of two subscribing Witnesses.

ROBERT L. INIGCARTNEY.

Witnesses:

SUMNER SIBERELL, INA M. CRILEY. 

